At the same time, in the artificial dimension—
While the members of the three major peerages had long since departed for their own affairs, a figure reappeared within a certain snow-capped mountain.
This figure was none other than Yukinoshita Yukino, who had already finished her work for the day.
After completing her daily duties, Yukinoshita Yukino had actually returned to the artificial dimension to train.
Because—
"Ice Princess!"
At Yukinoshita Yukino's cold command, the three-meter-tall heteromorphic princess behind her opened her icy lips and exhaled a breath of freezing air.
The scale of the freezing air wasn't large; on the contrary, it was quite slender. However, this breath was like a localized blizzard or an icy arrow. Wherever it passed, whether through the atmosphere or across the vast white snowfields, instant freezing occurred. Countless shards of ice rapidly grew along the path of the freezing air.
Yukinoshita Yukino stared intently at the frost until it reached another mountain peak, turning it into a mountain of ice, before finally withdrawing her gaze.
Then, she murmured to herself.
"As expected, this is the limit of what 'Eternal Ice Princess' can achieve at its current stage."
Yukino turned her gaze toward the heteromorphic princess behind her.
At first glance, the Ice Princess seemed the same as always, standing there silently, radiating terrifying cold and pressure. But only Yukino could sense that the Ice Princess was currently in a strange state.
In the past, whether under Yukino's direct control or acting autonomously, the Ice Princess behaved like a living entity, responding and moving rapidly without the slightest lag. Now, however, her reactions were noticeably slower, as if she had become sluggish, taking a second or two to respond to commands.
Even the Ice Princess's power seemed to have become unstable. Yukino had unleashed the same attack three times in a row, but the power varied each time—sometimes fluctuating wildly. At its peak, it exceeded the frost she could produce at full strength, but at its lowest, it wasn't even as strong as a basic magic strike from when she first reincarnated as a devil.
Something was clearly wrong.
Moreover, this abnormal condition had been persisting for several days.
That was why Yukino had been hiding it from everyone, quietly returning to the artificial dimension late at night after work to research and experiment with the "Eternal Ice Princess."
Today, she finally understood the fundamental reason why her Sacred Gear had become like this.
"It is standing at a crossroads, unsure of which direction to take."
That was the essence of it.
After months of training and hard work—especially after the special training in the Underworld and her recent efforts in this dimension—Yukino's mastery and control over her Sacred Gear had grown exponentially. Compared to the beginning, it was like night and day.
As her control deepened, she had finally pushed the power to its limit, arriving at a fork in the road.
"A Sacred Gear is not static. It either evolves based on the host's will or crosses into a new realm due to intense psychological shifts—the so-called Balance Breaker."
"My 'Eternal Ice Princess' is currently at this boundary, with two paths of evolution laid out before it."
"One is a standard reinforcement of the Sacred Gear itself to increase its power. The other is to step into that new realm and achieve Balance Breaker."
Having thoroughly read all the books regarding Sacred Gears in the estate's library and having consulted Leon and Kiba Yuuto—two individuals who had already reached the realm of Balance Breaker—Yukino quickly identified the problem.
Simply put, her growth had been so startlingly fast that her Sacred Gear encountered two upgrade paths simultaneously. Because it didn't know which path to take, it had fallen into a sort of "stalled" state, becoming sluggish and inconsistent in its power output.
The solution was simple: the host had to give it a push and force it to commit to one path.
Once that happened, the Sacred Gear would undergo a distinct transformation. Its internal system would not only return to normal but become significantly more powerful.
However, whether it would be a standard reinforcement or a direct ascent to the Balance Breaker realm required Yukino's careful consideration.
"If I just want to strengthen the Sacred Gear's power, it shouldn't be difficult. It just needs a little stimulation."
"But to achieve Balance Breaker, there must be a profound psychological shift."
Having grasped the situation, Yukino's brow furrowed deeply.
She knew this was a rare, sought-after opportunity.
The fact that her Sacred Gear was in this state proved she was standing right at the threshold of the ultimate realm. If she could step through, her strength would skyrocket. Perhaps she could even reclaim her title as the strongest in the Eligos peerage.
Ever since Ram, the Child of the Oni, joined the peerage, Yukino—who had always held the top spot—had been displaced. Even Rem, when transformed, could become stronger than her, and even Ravel could use her immortality and elemental advantage to wear Yukino down. This weighed heavily on the ever-proud Yukino.
Consequently, after Ravel and the others joined, Yukino had become exceptionally diligent and hardworking.
Today, she finally faced another chance for metamorphosis.
If she could reach Balance Breaker, her strength would improve vastly, and defeating Ram would no longer be an impossibility.
The prerequisite, however, was actually completing the Balance Breaker, not just a common power-up.
"A profound psychological shift..."
Yukino began to feel troubled.
She certainly didn't want to miss the chance to reach the Balance Breaker realm.
But she had no clue how to trigger such an intense change in her own psyche.
She was naturally cold and composed. While her inner thoughts weren't as sparse as her exterior suggested—in fact, they were quite rich—her personality made it difficult for her to experience extreme emotional swings.
Because she had seen through too many things at a young age, she rarely felt strongly about anything anymore. Her indifferent attitude toward most people only reinforced this.
Asking someone like Yukinoshita Yukino to find a way to induce a violent mental shift was a tall order.
"...Should I go pick a fight with my sister?"
The thought crossed her mind.
If there was anyone who could make the cold Yukino lose her temper and experience complex emotions, it was undoubtedly her older sister, Yukinoshita Haruno.
Haruno was an expert at stepping on her sister's emotional triggers, leaving her either half-dead with rage or utterly exasperated. Yukino had a massive amount of "grievance" stored up regarding her sister.
If she could have a real shouting match with Haruno, Yukino was certain she could reach Balance Breaker.
The problem was—
"Sister is always teasing me, but she never actually fights with me."
Yukino was well aware of this.
If Leon were here, he would have told her: Your sister is just a sister-con. She isn't as extreme as a certain Devil King girl, so she expresses her obsession by constantly poking at you to get your attention.
Therefore, under normal circumstances, Haruno wouldn't actually argue with Yukino.
Yukino didn't know the specifics, but she knew Haruno usually maintained a smiling facade. Even if Yukino tried to pick a fight, Haruno would likely laugh it off and brush her aside. In the end, instead of reaching her goal, she might just trigger enough minor emotion to push the Sacred Gear toward the "standard reinforcement" path.
That would be a net loss.
Furthermore, ever since she moved into Leon's estate and became his servant, her sister's attitude had undergone a subtle change.
In the past, even when Yukino moved out of the family home into an apartment, Haruno would ambush her every few days, claiming she wanted to "exchange feelings" and check on her sister's solitary life.
But now, Haruno hadn't appeared in Yukino's life for a long time. Even phone calls had become sparse. Occasionally, their mother—who usually acted indifferent—would call to get a general idea of her status.
As for Haruno... the distance between her and Yukino seemed to have suddenly stretched very far. She was no longer everywhere, as she once seemed to be.
Thinking of this, Yukino's mood became complicated.
She knew it wasn't that Haruno was moving away from her, but that she was moving away from Haruno.
In the past, Haruno could care about her life, her studies, and even her romantic interests.
But now?
Yukino's life had become the life of a Devil. Her studies were no longer about the human world, but the knowledge of the Underworld. Her days were spent handling Devil business, training her magic, and mastering her Sacred Gear. Haruno understood none of this, so how could she care for it?
She and her sister were now people of two different worlds.
Her sister would eventually be the helmsman of the Yukinoshita family, a social elite, and a noble daughter. She would likely marry a man of equal status under the family's arrangement and spend the rest of her life with him until she passed away at a ripe old age, leaving everything behind.
Yukino, on the other hand, would follow Leon back to the Underworld to revive the Eligos house. As a member of the Eligos peerage, she would manage territory or participate in Rating Games, competing against various powerhouses until she could stand on her own as a High-Class Devil. Then, she could become a "King" herself, recruit her own peerage, and assist Leon in bringing glory to the Eligos name in the supernatural world.
A hundred years?
By then, Yukino likely wouldn't have even exhausted one percent of her lifespan.
When her sister reached the end of her life, Yukino would probably still look exactly as she did now.
Yukino didn't quite know what she was feeling, but it suddenly occurred to her that her sister had probably already experienced this realization.
"...I'll find a chance to go back and see her."
Yukino let out a sigh, retracted the Ice Princess, and walked out of the frozen wasteland.
She was going back.
Since the person most likely to cause a stir in her heart was off-limits, she would go find the next best person.
Chiba, Leon's Estate—
Returning from the artificial dimension, Yukino left the basement and immediately headed toward Leon's room.
Soon, she arrived outside his door and knocked.
"Are you asleep?"
Yukino asked directly, but received no response.
"Not here?"
Her brow furrowed. She pushed the door open and walked right in.
She wasn't the type to barge into someone's room, but if that person was Leon, it was a different story.
Because when he entered her room, he basically never knocked.
Even if she was changing or sleeping, he would push the door open and, while she was staring at him dumbfounded, toss out a line like:
"I'm entering my own servant's room; surely I don't need to knock, do I?"
The first time she heard that self-righteous excuse, she wanted to kill him.
If she hadn't been holding up a single piece of fabric that would have fallen if she moved, she definitely would have attacked him.
Since then, Yukino had learned to enter Leon's room directly; knocking was merely a symbolic gesture of politeness.
And so, Yukino walked into Leon's room. She saw two empty tea cups on the table and a few pieces of clothing tossed aside.
Then... she heard certain noises coming from the bathroom.
As she listened, her ears began to turn red.
"That bastard—"
Yukino's teeth began to itch with frustration.
Well, before Yukino returned, Leon—having finished his tea—had taken the opportunity to invite Asuna to bathe with him.
Normally, this wasn't such a big deal, as it had happened before.
But this time, there was no one else; it was just the two of them.
Under such circumstances, how could Leon possibly restrain himself?
The blushing and flustered Asuna had been dragged in, becoming like meat on a chopping block, devoured whole by a certain someone.
Having guessed the general direction of events, Yukino felt a wave of bitterness in her heart after a moment of gnashing her teeth.
Even though... she was clearly the first one here...